Need Results From One Combo Box To Populate Other Combo Box

I am a self-admitted beginner so go easy . I have a query populated with
all of my data. I am building a form based on two columns in the query: Pick Up Name, and
Deliver to Name. Lets say I have records for company XYZ picking up at location A three
seperate times, location B once, and location C four times. On the form I want to have
my first combo box listing all the names of column "Pick Up Name". When I scroll down and
select company XYZ, I want my second combo box to only display the three locations where
company XYZ has picked up: A, B and C. Then I want the option of selecting either A, B or
C and in a third box, display total number of times that company XYZ has picked up at
selected location.

For example, I select company XYZ from the first drop-down. I select C from the second
drop-down, from the list of three locations. I get a result of four, because company XYZ
has delivered to location C four times.

Right now, I have my first combo box with the Pick Up Name data, where do I go from here?
Any help or nudges in the right direction greatly appreciated!